The invention relates to a method of producing luminous decorations with good wear resistance on ceramics and silicate bases, such as porcelain, stoneware, pottery, enamel or glass. The decorations are produced by means of stoving or baking with decorative colors (vitrifiable colors, overglaze colors), lustring preparations and noble-metal preparations.
Decorative colors as well as lustring and noble-metal preparations are widely used for the decoration of ceramic and silicate surfaces. They are described e.g. in "Ullmanns Enzyklopadie der technischen Chemi", vol. 17 (1977) under the entry "Keramische Farben" (Ceramic Colors). The term "decorative colors" denotes vitrifiable colors and overglaze colors.
It is difficult to incorporate decorative colors along with lustring and noble-metal preparations into a decoration, since few of the metallic elements contained in the lustring and noble-metal preparations react with the decorative colors during stoving to produce heavily colored products. For example, gold brings about an intensive violet coloration and silver brings about a discoloration tending toward yellowish brown. In addition to the discoloration at the contact areas between decorative colors and the lustring or noble-metal preparations, most decorative colors suffer because of their transparency. There is a considerable loss of their luminosity as a result of the dark color of the lustring or noble-metal layers under them.
DE-OS 29 45 288 teaches the application of heat-transferring silicate coatings onto heat-resistant ceramic objects. The silicate coatings comprise an enamel to which at least 10% by weight mica particles coated with titanium dioxide has been added. However, these enamels are not used to produce luminous decorations in cooperation with lustring and noble-metal preparations.